What does 1 Corinthians 7:22 mean?

In the previous verse, Paul applied the principle message of this chapter to those defined as "slaves" in Greco-Roman culture. He has written that those who are married should stay married and those who are single do not necessarily need to get married. Those who are circumcised—or not—should stay as they are. Now he has added that even slaves should not make the primary focus of their lives changing that status, though they should absolutely take the opportunity to become free if it comes along.

Paul calls Christians to elevate the status they hold in God's eyes above their status in the eyes of the world. Someone who comes to Christ as a "slave" under Roman law is seen by God as a freedman. He or she has been freed from the power and the penalty of their sin. By God's grace and through faith in Christ, that human slave is free to share in God's glory forever and will eternally enjoy all the rights and privileges of royalty in the kingdom of God.

The reverse is also true. Those who come to Christ as Roman citizens or freedmen must understand that, in the eyes of the Lord, they serve as "slaves"—as bondservants—of Christ. They exist in body and spirit to joyfully serve the purposes of God in this world and the next. Paul often referred to himself as a slave of Christ, holding that badge of honor high above his merely human status as a Roman citizen.

For these reasons, and in that context, Paul tells believing slaves not to become preoccupied with their human status. They should take opportunity when given (1 Corinthians 7:21), but don't need to see it as mandatory. God will use them right where they are for His greater good.